Active antenna arrays have the potential to improve and expand the capability and reliability of commercial and military ground, shipboard, airborne, missile, and space-based radar and communications systems. The primary components and cost drivers of such active array antennas tend to be microwave multi-chip modules incorporating monolithic microwave integrated circuits (MMICs) and the power supplies which must be associated with the modules. Such modules are often know as transmit-receive (TR) modules. These primary components or modules are often packaged in assemblies known as line replaceable units (LRUs), which typically incorporate a common mounting plate, control and power conditioning circuitry, and component-to-component interconnects.
The performance and reliability of the TR module and power supply components are directly dependent upon the temperature at which they operate. More specifically, performance is enhanced and reliability is improved when the component temperatures are minimized. It has been found that provision of convection air cooling may not be practical due to the large heat loads and space constraints, which limit the cross-sectional areas of air movement paths. As a result, a common cooling scheme is to connect the structure of the TR module to a liquid-cooled “cold plate,” with component locations and structures designed to reduce the thermal resistance to the cold plate. When the cold plate is itself fluid or liquid cooled, the component locations and structures are designed to reduce the thermal resistance to the coolant.
While the liquid-cooled cold plate provides great advantages insofar as maintaining low component temperatures is concerned, the need for the heat generated by the components to pass through a physical juncture between the LRU and the cold plate still tends to keep the component temperatures higher than may be desired for maximum-performance equipment. The need for maximum performance in conjunction with low operating temperatures has led to the mounting of the heat-generating components directly to the liquid-cooled cold plate, without an intermediary structure. In such an arrangement, the line replaceable unit itself is liquid-cooled. This is a very advantageous system from the point of view of performance and reliability maximization, but may lead to other problems. In particular, the liquid fittings and interconnects which are required to transfer the liquid coolant into and from the LRU imposes limits on the accessibility and therefore maintainability. In particular, when an LRU exhibits degraded performance, it may be desirable to change it out with a properly operating replacement LRU, and the liquid connection fittings and interconnects contribute to the time and effort required to make such a changeover.
The problem associated with the need to disconnect and reconnect liquid coolant paths when working on LRUs or changing over between LRUs has been addressed in the past by the use of liquid quick-connect or quick-disconnect (QD) fittings, which allow rapid connection andor disconnection of the liquid lines. In the context of densely packed equipment, such as is found, for example, in active antenna arrays, packaging requirements may dictate that the liquid quick-disconnect fittings be of the “blind-mate” type, which in principle do not require that the fittings be visible during the disconnection or connection process.
Improved fluid connection arrangements are desired.